IIT-M to develop tech to reduce noise pollution in Chennai

Chennai: IIT Madras is developing an engineering-based technology to reduce urban sound levels in city's major junctions by targeting how sound propagates. The noise mitigation system is centred on acoustic resonators and barrier mechanisms designed to absorb and deflect sound waves in high-exposure environments.Professor S M Shiva Nagendra, department of civil engineering, IIT-M, said the team is aiming for developing a system that can reduce noise pollution by 30-40 decibels. "If we achieve even a 30-40 decibel reduction, it will transform high-noise zones into significantly calmer environments," he said.The proposed system uses locally available and engineered materials, including porous media, PVC-based resonators and vegetative buffers, to create sound attenuation structures. The team plans to set up the system at high-noise urban hotspots such as the Cancer Institute junction in Chennai, a designated sensitive zone, after validating its performance.The intervention builds on IIT-M's recent citywide noise mapping study, released at the Tamil Nadu Climate Summit 4.0, which provides a detailed assessment of Chennai's acoustic environment. Based on real-time monitoring using a network of low-cost sensors across 60 locations, the study found that road traffic is the dominant source of noise.CPCB norms prescribe limits of 65 decibels during the day in commercial areas and 55 decibels in residential areas. Spatial analysis identified Valasaravakkam as one of the worst-affected zones exceeding these limits due to congestion, traffic and construction activity, while relatively quieter areas such as Adyar benefit from green cover and institutional land use. Noise levels in several hotspots frequently exceeded 70 decibels, including near hospitals and urban health centres. "Both natural elements such as vegetation and engineered structures can act as barriers. If designed well, they can significantly attenuate noise," the professor said.